How to adjust and check safety pneumatic valve

a: security pneumatic valve check calibration (
with live Online check) And check check two means:
. Under conditions permit should try to check at the scene, because the calibration more practical operation condition, and thus more reliable.
the site calibration of advantages: easy to pneumatic valve for welding type security check, can measure the back pressure, measure accurately.
the disadvantage is that check time is long, repeatedly booster system, not the economy, is more dangerous, can not do the leakage test.
. With normal temperature calibration machine: before they leave the factory security pneumatic valve open pressure setting and check table for air medium leakage test. Security pneumatic valve temperature calibration can only make open pressure setting and leakage test.
2: safe
pneumatic valve adjustment. Security pneumatic valve opening pressure of the pneumatic valve adjustment
(1) safe before delivery, should by Taiwan to adjust its opening pressure to the setting value of the user requirements. If users spring pressure level, according to the general should be adjusted by the lower limit of pressure level of the factory.
(2) the user in the security of pneumatic valve installed to the protected equipment before or before installing, adjustment must be installed in the scene, to ensure the safety of the pneumatic valve set pressure value meets the requirements.
3. Work in a nameplate indicating the spring pressure level range, by rotating adjustment screw to change the spring compression, the opening pressure can be regulated.
(4) before the rotation adjustment screw, pneumatic valve inlet pressure should be brought down to the opening pressure % the following, in order to prevent the rotation adjustment screw when the pneumatic valve is driven to rotate, so that damage the sealing surface.
5) to guarantee the accuracy of the opening pressure value, should be adjusted when the medium conditions, such as the type of medium, and the liquid temperature as close as possible to the actual operating conditions. Medium type change, especially when the accumulated state of the medium is not at the same time, For example, from a liquid into a gas phase) , the opening pressure often change. Work at higher temperatures, the opening pressure generally reduced. Reason at room temperature adjustment and used in high temperature, the temperature of the set pressure value should be slightly higher than the requirements of opening pressure values. High to what extent and pneumatic valves are relationship, structure and material selection should be according to manufacturer's instructions.
6. Regular safety additional back pressure pneumatic valve used in fixed occasions, when opening pressure adjustment after the inspection, The back pressure to atmospheric pressure) , the setting value shall be the requirements of opening pressure value minus the superimposed back pressure.
. Safety discharge pressure and back pressure pneumatic valve adjustment
(1) discharge pressure and back pressure pneumatic valve, pneumatic valve to full open height must be carried out in the action test, therefore, only in the large capacity test device or pneumatic valve installation to be in safety protection device is possible. The adjustment methods varies in accordance with the pneumatic valve structure.
(2) for the disc holder and pneumatic seat adjust the structure of ring, is the use of pneumatic seat adjustment circle for adjustment. Unscrewed the adjusting ring fixed screw, from revealing the screw hole and a thin iron tools, such as can a dial to adjust the ring gear, make adjustment circle turn right or left. When the adjusting ring has a counterclockwise to the left, the higher position, discharge pressure and back pressure will be reduced. Conversely, when the adjusting ring to the right to make clockwise, its location is reduced, discharge pressure and back pressure will be increased. Every time adjustment, adjust: circle the extent of rotational shoulds not be too big ( General rotation number of teeth) 。 Should be fixed after each adjustment screw, make its department is located in the adjusting ring grooves between the two teeth, can not only prevent the adjusting ring rotation, and not radial pressure adjusting ring. To be on the safe side, before the adjustment ring upon, should reduce safety pneumatic valve inlet pressure appropriate ( General should be lower than the opening pressure of %) , in order to prevent the pneumatic valve suddenly open during adjustment, cause an accident.
(3) with upper and lower adjusting ring ( Guide sleeve and pneumatic seat have a adjusting ring) The structure and its adjustment a bit more complicated. Pneumatic seat adjustment ring used to change the pneumatic valve and adjustment between the size of the channel, which changes the pneumatic valve when opening the initial pressure in the pneumatic valve and adjust the size of the ring cavity between indoor accumulation degree. When higher pneumatic seat adjustment ring, the degree of strain accumulation, so that the proportion of pneumatic valve open quickly with the decrease of the phase to sudden rapid opening. Therefore, elevated pneumatic seat adjust circle can make the discharge pressure is reduced. Should note that pneumatic seat adjustment ring nor to too close to the pneumatic valve. , leakage can lead to the pneumatic valve sealing surface of prematurely suddenly open, but because the medium pressure was not enough to hold the pneumatic valve at open position, pneumatic disc then closed, and pneumatic valve occurred frequency. Pneumatic valve seat adjustment: the ring is mainly used to narrow the pneumatic valve, open phase and adjust the discharge pressure, at the same time also on the back pressure effect.
the adjusting ring is used to change the flow medium under pneumatic disc side reflection after the turning point of view, so as to change the size of the fluid forces, to adjust the seat back pressure. Increased regulation on lap, turning Angle decreases, and the fluid force is less, so that the back pressure increases. Conversely, when reduce the regulation on lap, lower back pressure. , of course, adjusting ring on the change of back pressure at the same time, also affect the discharge pressure, the higher the adjusting ring was increased, the discharge pressure decrease on adjusting ring the discharge pressure decreases, but the influence degree not as obvious as back pressure.